This invention relates to devices used in transperineal brachytherapy and more specifically to a urethral catheter that contains hypoechoic microspheres that are recognizable by transrectal ultrasonography (TRUS).
Prostate cancer is one of the most common cancers in men. One often used treatment for localized prostate cancer is transperineal brachytherapy. Transperineal brachytherapy involves the delivery of an implantable radioactive delivery source to the prostate while limiting exposure to adjacent tissues. Delivery is achieved by implanting radioactive xe2x80x9cseedsxe2x80x9d directly into the prostatic stroma. The seeds typically comprise a radioactive isotope, such as Iodine 125, Palladium 103 or iridium. The accuracy of the implantation is critical to avoid damaging surrounding tissues, post-operative morbidity and potential urologic complications. However, accurate placement of the radioactive material is highly dependent on the skill of the surgeon and the surgeon""s ability to identify anatomic landmarks such as the posterior urethra, bladder neck and external urinary sphincter. The surgeon""s ability to visualize the internal topography of the patient""s organs and tissues depends, in part, on the equipment used. The internal topography is typically visualized, and the implantation guided, by transrectal ultrasonography (TRUS). However, the usefulness of transrectal ultrasonography is limited by the less than optimal acoustic properties of the human anatomy.
It is therefore a primary object of this invention to provide a urethral catheter which compliments and facilitates transperineal brachytherapy in the management of localized prostate cancer.
It is a further object of this invention to provide a urethral catheter which contains hypoechoic microspheres that are recognizable by transrectal ultrasonography.
It is a further object of this invention to provide a urethral catheter which includes a plurality of hyperechoic markers along its length to allow a surgeon to accurately determine prostatic urethral lengths.
It is a further object of the invention to provide a catheter which improves the surgeon""s ability to identify critical anatomic landmarks using transrectal ultrasonography.
It is a further object of the invention to provide a urethral catheter for transperineal brachytherapy which is disposable.
It is a further object of the invention to provide a device which increases the surgeon""s ability to accurately determine the location of the bladder neck and external urinary sphincter during transperineal brachytherapy to properly distribute the implanted radioactive material uniformly to enhance the clinical outcome of the treatment.
It is a further object of this invention to provide a urethral catheter which reduces postoperative morbidity and potential urologic complications associated with transperineal brachytherapy.
A preferred embodiment of the urethral catheter of the invention, which is adapted to facilitate transperineal brachytherapy, generally comprises: a sleeve having a proximal end, a distal end and at least one lumen at least partially filled with a masma comprising a plurality of hypoechoic microspheres; an inflatable balloon fixed about the sleeve proximate the distal end; an inflation valve proximate the proximal end; and a channel, integral with at least a portion of the sleeve, for transporting an inflation medium from the valve to the balloon. The sleeve preferably defines an outer wall and an inner wall defining at least said one inner lumen that is at least partially filled with a masma comprising a plurality of hypoechoic microspheres, wherein the channel is interposed between the outer wall and the inner wall. The sleeve is preferably made of latex and the entire catheter is preferably disposable after just a single use.
The inflation medium may comprise one or more gaseous components, and/or one or more fluids; wherein the balloon is preferably adapted to be inflated with the inflation medium to a volume of about 5 cubic centimeters.
The plurality of microspheres are adapted to appear sufficiently hypoechoic to create an acoustic shadow when viewed by transrectal ultrasound. In addition to the hypoechoic microsphere, the sleeve may further comprise one or more hyperechoic markers between the distal end and the proximal end, wherein the hyperechoic markers may comprise circumferential ribs that are integral with the sleeve and are provided at 1 centimeter (cm) intervals.